This invention relates to vehicular skid control systems and more particularly to an improved indicator device for indicating certain functional failures in such a system.
Skid control systems generally provide a mechanism' for automatically relieving the brake pressure during an incipient skid condition to prevent skidding and loss of vehicular control. These systems are, for the most part, fully automatic and require no pumping of the brakes by the vehicle operator.' In fact, most commercial systems anticipate that the vehicle operator will maintain brake pressure during the incipient skid condition. Since the device is fully automatic the operator may not even sense its operation. Thus, it may be difficult for the vehicle operator to tell when the skid control system is inoperative. In the absence of some indication of this malfunction, control of the vehicle may be lost during braking.
It is, therefore, a principal object of this invention to provide a skid control system incorporating an indicating device for indicating malfunctioning of the skid control system.
It is another object of the invention to provide an improved and simplified fail safe indicator for a vehicular skid control system.
In certain types of skid control systems a bypass arrangement may be provided for bypassing the modulator in the event of a failure condition. It has been proposed to provide an indication of failure when the bypass system goes into its failure mode. However, such a system is not completely indicative of a failure in the overall brake circuit. For example, even though the system goes into a failure mode the master cylinder may still provide sufficient actuating pressure for the brakes.
It is, therefore, a further object of this invention to provide a skid control system embodying a failure indicator that provides an indication to the vehicle operator when the master cylinder is actuated and actuating pressure is not transmitted to the wheel cylinders.